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a52fde77 | 1 | /******************************************************************************* |
ed902a2b | 2 | * Copyright (c) 2012, 2014 Ericsson |
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3 | * Copyright (c) 2010, 2011 École Polytechnique de Montréal |
4 | * Copyright (c) 2010, 2011 Alexandre Montplaisir <alexandre.montplaisir@gmail.com> | |
5df842b3 | 5 | * |
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6 | * All rights reserved. This program and the accompanying materials are |
7 | * made available under the terms of the Eclipse Public License v1.0 which | |
8 | * accompanies this distribution, and is available at | |
9 | * http://www.eclipse.org/legal/epl-v10.html | |
5df842b3 | 10 | * |
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11 | *******************************************************************************/ |
12 | ||
e894a508 | 13 | package org.eclipse.tracecompass.statesystem.core.backend; |
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14 | |
15 | import java.io.File; | |
16 | import java.io.FileInputStream; | |
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17 | import java.util.List; |
18 | ||
feea3b3c | 19 | import org.eclipse.jdt.annotation.NonNull; |
aa353506 | 20 | import org.eclipse.jdt.annotation.Nullable; |
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21 | import org.eclipse.tracecompass.statesystem.core.exceptions.StateSystemDisposedException; |
22 | import org.eclipse.tracecompass.statesystem.core.exceptions.TimeRangeException; | |
23 | import org.eclipse.tracecompass.statesystem.core.interval.ITmfStateInterval; | |
24 | import org.eclipse.tracecompass.statesystem.core.statevalue.ITmfStateValue; | |
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25 | |
26 | /** | |
27 | * The main difference between StateSystem and StateHistorySystem is that SHS | |
28 | * allows 'seeking' back in time to reload a Current State at a previous time. | |
29 | * "How to go back in time" is defined by the implementation of the | |
30 | * HistoryBackend. | |
5df842b3 | 31 | * |
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32 | * A StateHistorySystem contains one and only one HistoryBackend. If you want to |
33 | * use a paradigm with more than one provider (eg. more or less precision | |
34 | * depending on what's asked by the user), implement one wrapper HistoryBackend | |
35 | * which can then contain your 2-3 other backends underneath. | |
5df842b3 | 36 | * |
bcec0116 | 37 | * @author Alexandre Montplaisir |
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38 | */ |
39 | public interface IStateHistoryBackend { | |
40 | ||
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41 | /** |
42 | * Get the ID of the state system that populates this backend. | |
43 | * | |
44 | * @return The state system's ID. | |
dbc7991d | 45 | * @since 1.0 |
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46 | */ |
47 | @NonNull String getSSID(); | |
48 | ||
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49 | /** |
50 | * Get the start time of this state history. This is usually the same as the | |
51 | * start time of the originating trace. | |
5df842b3 | 52 | * |
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53 | * @return The start time |
54 | */ | |
57a2a5ca | 55 | long getStartTime(); |
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56 | |
57 | /** | |
58 | * Get the current end time of the state history. It will change as the | |
59 | * history is being built. | |
5df842b3 | 60 | * |
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61 | * @return The end time |
62 | */ | |
57a2a5ca | 63 | long getEndTime(); |
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64 | |
65 | /** | |
66 | * Main method to insert state intervals into the history. | |
5df842b3 | 67 | * |
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68 | * @param stateStartTime |
69 | * The start time of the interval | |
70 | * @param stateEndTime | |
71 | * The end time of the interval | |
72 | * @param quark | |
73 | * The quark of the attribute this interval refers to | |
74 | * @param value | |
75 | * The StateValue represented by this interval | |
76 | * @throws TimeRangeException | |
77 | * If the start or end time are invalid | |
78 | */ | |
79 | // FIXME change to IStateInterval? | |
57a2a5ca | 80 | void insertPastState(long stateStartTime, long stateEndTime, |
aa353506 | 81 | int quark, @NonNull ITmfStateValue value) throws TimeRangeException; |
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82 | |
83 | /** | |
84 | * Indicate to the provider that we are done building the history (so it can | |
85 | * close off, stop threads, etc.) | |
5df842b3 | 86 | * |
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87 | * @param endTime |
88 | * The end time to assign to this state history. It could be | |
89 | * farther in time than the last state inserted, for example. | |
90 | * @throws TimeRangeException | |
91 | * If the requested time makes no sense. | |
92 | */ | |
57a2a5ca | 93 | void finishedBuilding(long endTime) throws TimeRangeException; |
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94 | |
95 | /** | |
96 | * It is the responsibility of the backend to define where to save the | |
97 | * Attribute Tree (since it's only useful to "reopen" an Attribute Tree if | |
98 | * we have the matching History). | |
5df842b3 | 99 | * |
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100 | * This method defines where to read for the attribute tree when opening an |
101 | * already-existing history. Refer to the file format documentation. | |
5df842b3 | 102 | * |
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103 | * @return A FileInputStream object pointing to the correct file/location in |
104 | * the file where to read the attribute tree information. | |
105 | */ | |
57a2a5ca | 106 | FileInputStream supplyAttributeTreeReader(); |
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107 | |
108 | // FIXME change to FOS too? | |
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109 | /** |
110 | * Supply the File object to which we will write the attribute tree. The | |
111 | * position in this file is supplied by -TreeWriterFilePosition. | |
112 | * | |
113 | * @return The target File | |
114 | */ | |
57a2a5ca | 115 | File supplyAttributeTreeWriterFile(); |
a52fde77 | 116 | |
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117 | /** |
118 | * Supply the position in the file where we should write the attribute tree | |
119 | * when asked to. | |
120 | * | |
121 | * @return The file position (we will seek() to it) | |
122 | */ | |
57a2a5ca | 123 | long supplyAttributeTreeWriterFilePosition(); |
a52fde77 | 124 | |
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125 | /** |
126 | * Delete any generated files or anything that might have been created by | |
127 | * the history backend (either temporary or save files). By calling this, we | |
128 | * return to the state as it was before ever building the history. | |
5df842b3 | 129 | * |
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130 | * You might not want to call automatically if, for example, you want an |
131 | * index file to persist on disk. This could be limited to actions | |
132 | * originating from the user. | |
133 | */ | |
57a2a5ca | 134 | void removeFiles(); |
36bf82a2 | 135 | |
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136 | /** |
137 | * Notify the state history back-end that the trace is being closed, so it | |
138 | * should release its file descriptors, close its connections, etc. | |
139 | */ | |
57a2a5ca | 140 | void dispose(); |
1a4205d9 | 141 | |
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142 | // ------------------------------------------------------------------------ |
143 | // Query methods | |
144 | // ------------------------------------------------------------------------ | |
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145 | |
146 | /** | |
147 | * Complete "give me the state at a given time" method 'currentStateInfo' is | |
148 | * an "out" parameter, that is, write to it the needed information and | |
149 | * return. DO NOT 'new' currentStateInfo, it will be lost and nothing will | |
150 | * be returned! | |
5df842b3 | 151 | * |
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152 | * @param currentStateInfo |
153 | * List of StateValues (index == quark) to fill up | |
154 | * @param t | |
155 | * Target timestamp of the query | |
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156 | * @throws TimeRangeException |
157 | * If the timestamp is outside of the history/trace | |
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158 | * @throws StateSystemDisposedException |
159 | * If the state system is disposed while a request is ongoing. | |
a52fde77 | 160 | */ |
aa353506 | 161 | void doQuery(@NonNull List<@Nullable ITmfStateInterval> currentStateInfo, long t) |
3b7f5abe | 162 | throws TimeRangeException, StateSystemDisposedException; |
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163 | |
164 | /** | |
165 | * Some providers might want to specify a different way to obtain just a | |
166 | * single StateValue instead of updating the whole list. If the method to | |
167 | * use is the same, then feel free to just implement this as a wrapper using | |
168 | * doQuery(). | |
5df842b3 | 169 | * |
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170 | * @param t |
171 | * The target timestamp of the query. | |
172 | * @param attributeQuark | |
173 | * The single attribute for which you want the state interval | |
ed48dc75 PT |
174 | * @return The state interval matching this timestamp/attribute pair, or |
175 | * null if it was not found | |
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176 | * @throws TimeRangeException |
177 | * If the timestamp was invalid | |
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178 | * @throws StateSystemDisposedException |
179 | * If the state system is disposed while a request is ongoing. | |
a52fde77 | 180 | */ |
57a2a5ca | 181 | ITmfStateInterval doSingularQuery(long t, int attributeQuark) |
ed48dc75 | 182 | throws TimeRangeException, StateSystemDisposedException; |
5df842b3 | 183 | |
a52fde77 | 184 | } |